Reducing Health Care Workers Absenteeism in Covid-19 Pandemic Through BCG Vaccine

Overview

Rationale: Covid-19 spreads rapidly throughout the world. A large epidemic in the Netherlands would seriously challenge the available hospital capacity, and this would be augmented by absenteeism of healthcare workers (HCW). Strategies to prevent absenteeism of HCW are, therefore, desperately needed to safeguard continuous patient care. Bacille Calmette-Guérin (BCG) is a vaccine against tuberculosis, with protective non-specific effects against other respiratory tract infections in in vitro and in vivo studies, and reported significant reductions in morbidity and mortality. The hypothesis is that BCG vaccination can reduce HCW absenteeism during the epidemic phase of Covid-19. Objective: Primary objective: To reduce absenteeism among HCW with direct patient contacts during the epidemic phase of Covid-19. Secondary objective: To reduce hospital admission, ICU admission or death in HCW with direct patient contacts during the epidemic phase of Covid-19. Study design: A placebo-controlled adaptive multi-centre randomized controlled trial. Study population: HCW with direct patient contacts among which nurses and physicians working at emergency rooms and wards where Covid-19-infected patients are treated. Intervention: Participants will be randomized between intracutaneous administration of BCG vaccine or placebo in a 1:1 ratio. Main study parameters/endpoints: Primary endpoint: number of days of (unplanned) absenteeism for any reason. Secondary endpoints include the number of days of (unplanned) absenteeism because of documented Covid-19 infection, and the cumulative incidence of hospital admission, Intensive Care Admission, and death. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: Based on previous experience and randomized controlled trials in adult and elderly individuals, the risks of BCG vaccination are considered low. The objective of this trial is to evaluate the beneficial effects of BCG vaccination through a lower work absenteeism rate of HCW and/or a mitigated clinical course of Covid-19 infection. The primary endpoint and the adaptive design with frequent interim analyses facilitate maximum efficiency of the trial, so that results can inform policy making during the ongoing epidemic.

Since the beginning of 2020, SARS-CoV-2 spread rapidly throughout China and the rest of the world, with on 27 February 2020 the first detected case in the Netherlands. According to the WHO, Health-care workers (HCW) face an elevated risk of exposure to - and infection of Covid-19. Bacillus Calmette-Guérin (BCG) was developed as a vaccine against tuberculosis, but studies have shown its ability to induce potent protection against other infectious diseases: the so called non-specific effects (NSEs). A favorable in vitro or in vivo effect has been observed in studies for distinct viral pathogens, e.g. respiratory syncytial virus, yellow fever, herpes simplex virus; human papilloma virus. Based on the capacity of BCG to reduce the incidence of respiratory tract infections in children, to exert antiviral effects in experimental models; and to reduce viremia in an experimental human model of viral infection, the hypothesis is that BCG vaccination induces (partial) protection against susceptibility to and/or severity of Covid-19 infection. This study evaluates the efficacy of BCG to improve the clinical course of Covid-19 infection and to prevent absenteeism in order to safeguard continuous patient care. This randomized controlled trial has been designed as a pragmatic study with a highly feasible primary endpoint, which is unplanned absenteeism, that can be continuously measured on a bi-weekly basis). This allows for the most rapid identification of a beneficial outcome that would allow other HCWs to also benefit from the intervention if and as soon as it has been demonstrated to be effective.